Handling and treating combustible gases and vapors.



W. M. GROSVENOR.

HANDLING AND TREATING COMBUSTIBLE GASES APPLICATION FILED JUNE 21. 191:.

AND VAPORS.

Patented June 22, 1915.

4 SHEETSSHEET l.

W. M. GROSVENOR. HANDLING AND TREATING COMBUSTIBLE GASES AND VAPORS.

APPLICATION FILED JUNE 27,1911.

Patented June 22, 1915.

4 SHEETSSHEET 2- W. M. GROSVENOR.

HANDLING AND TREATING COMBUSTIBLE GASES AND VAPORS.

APPLICATION FILED JUNE 27,1911.

1,143,623. Patented June 22, 1915.

4 SHEETSSHEET 3- a L a o o l 5215311 3 E w 5 Q3 N i -Z q l I n i I l a i w\ l a i RI l w i l N m N f w 3 g 1 a R a; a o a 3 o I n 0 w 3 o g WITNESSES q. INVLN T016. 40% 1h W W. M. GROSVENOR. HANDLING AND TREATING COMBUSHBLE GASES AND VAPORS.

APPLICATION FILED JUNEZT, [9|].

Patented June 22, 1915.

4 SHEETSSHEET 4.

INVE/V TOR.

A TTOANE VS WITNESSES UNITED STATES PATENT OFFICE.

WILLIAM E. GBOSVENOR, 0F BIDGEWOOD, NEW JERSEY.

HANDLING AND TREATING COMBUSTIBLE GASES AND VAPOBS.

To all whom it may concern:

Be it known that I, WILLIAM M. Guosvn- NOR, a citizen of the United States, and a resident of Ridgewood, county of Bergen, and State of New Jersey, have invented certain new and useful Improvements in Handling and Treating Combustible Gases and Vapors, of which the following is a specification.

My invention relates to improvements in handling and treating combustible gases and vapors, and more particularly to the handling of combustible vapors evolved in the drying of various materials, such as the removal and recovery of solvents.

Two forms of apparatus are shown in the accompanying drawings adapted to carry out my improved method or process.

In the drawings, Figure 1 is a transverse vertical section through an apparatus adapted for treating celluloid and the like taken on the line GC of Fig. 2. Fig. 2 is a horizontal section of the same taken on the line AA of Fig. 1. Fig. 3 is another horizontal section of the same taken on the line B-B of Fig. 1. Fig. 4 is a vertical section through an apparatus adapted for the treating of artificial leather, taken on the line DD of Fig. 5. Fig. 5 is a section through the same taken on the line E-Eof Fig. 4. Fig. 6 is a section through the same taken on the line FF of Fig. 5. g

The object of my invention is to provide a method by which such vapors may be safely confined in such quantities as is usual in drying chambers, and may be economically condensed under conditions which will entirely eliminate or reduce to a minimum the liability to explosion, due to the mixture of air with the gases and vapors. These mixtures of air and gases or solvent vapors are not explosible when extremely impoverished in combustible vapor or gases, nor are they explosible if the mixture be made so rich in combustible vapor or gases that there is insufiicient oxygen for the propagation of the explosive wave.

Further objects, features and advantages will more clearly appear from the detailed description given below.

I find that in the drying of many materials such as celluloid and the like, it is possible to remove the greater portion of the Specification of Letters Patent.

Application filed June 27, 1911.

Patented June 22, 1915.

Serial No. 685,664.

solvents in an atmosphere so saturated as to be non-explosive, even at the elevated temperatures required to evaporate the solvents into a highly saturated atmosphere or surrounding medium. In this case however, it is found that the solvent can generally not be removed with suflicient completeness to produce a product which will be safe and permanent in storage, and which will not give off enough vapor to render disagreeable or dangerous the atmosphere of the room where quantities are stored. I find however, that if such materials be transferred from this saturated atmosphere to one where very impoverished solvent vapor conditions are maintained, the material will no longer give off sufficient vapors to render the atmosphere in its immediate neighborhood dangerous, and that the treatment of the material may be safely continued in the impoverished drying medium, as by more active condensation at a lower temperature.

From the above it will be clear that I provide an improved method for handling such vapors, and drying such materials, which consists in first, maintaining conditions which insure an excessive richness of the drying atmosphere, and thereafter continuing the treatment under conditions which insure excessive impoverishment of the combustible vapors in the drying atmos here. For instance, it has been determine mixtures of ethyl alcohol and air containing less than 3.95% alcohol or more than 13.65% are not explosive; that mixtures of air and ether containing less than 2.75% or more than 7.7% are not explosive; that benzol vapors containing less than 2.65% and more than 6.5%, or benzin containing less than 2.4% and more than 4.9%, or methyl alcohol containing less than 7.8% and more than 18%, and acetone containing less than 2.7% and more than about 15% are not explosive under ordinary conditions.

As an example, in the removing of solvents from celluloid according to my improvements, I carry out the treatment in two successive stages. During the first stage I provide the necessary physical and mechanical treatment of any well known charactor, to liberate the vapors of the solvents, acetone and methyl alcohol, and adjust their rate of removal either by adjusting the that amount of condensation or by adjusting the amount of air admitted, or otherwise, in such a manner that the atmosphere containin the wood alcohol and acetone is maintamed in a condition in which it has preferably more than 20% of the mixed vapors of acetone and wood alcohol. Under these conditions I am enabled to remove all the necessary liquid from the material to produce a plastic body ready for pressing and forming. I then subject the material to the further usual mechanical treatment and handling, and to a dr ing medium adjusted to contain not more t an 5% of the mixed vapors of acetone and alcohol, until the volatile liquids are removed to a sufficient extent to ermit any further treatment of the plastic material as may be desired, to be carried out with safety.

Referring to Figs. 1, 2 and 3 illustratin a machine for the treatment of celluloi 49 and 49 represent two chambers one above the other provided with side walls 50 and 50'. The chambers are provided with end walls 52, 52' and 53, 53', bottoms 54 and 54 provided with trap-doors 55 and 55, and top walls 56, 56' each of which is provided with an extension chamber 57, 57, the former serving as a closed connecting passage between the two chambers, and the latter as an inlet hopper for the entire apparatus. Both of the chambers 49 and 49 are provided with artitions 58 and 58 dividing ofi' the an s to form condenser chambers 60, 60 connected with the body of the main chambers at the top and bottom. The condenser chambers contain condensing pipes 61, 61 provided below with troughs 62, 62' to catch the condensed li uid which is carried away by pipes 63, 63 Fans 65, 65 circulate the gases activel in the drying-chambers proper. In each 0 the latter chambers is located a pair of sheeting rolls 66, 59 and 66, 59' of any well-known type, their shafts extending out through one side to the usual driving ears, not shown. Instead of being slit an stripped from the rollers by a hand-knife, I rovide a beam-knife 67, 67 for each pair 0 rollers actuated by the sprin -thrust rods 68, 68 and levers 69, 69'. nstead of the usual catch-boxes below the rollers there are provided two aprons, a return-apron 70 and 7 0 and a collection apron. The returnapron consists of a strong broad belt always trailing in the direction of the adjacent rollers'66, 66 over three uide rollers 71, 72 and 73. and 71, 72 and 3, two of which, 71, 72, 71 and 7 2' are rigidly set in an angleframe 74, 74', while the roller 73, 73' is attached thereto by spring take-up bearings 75, 75. The frame 74, 74' is rigidly attached to the worm gear 76, 76' and actuated by shaft 77, 77* and hand-wheel 78,

78 so that it may be swung back to the left about the shaft of roller 71, 71' as an axis to permit free movement forward of the collection-apron 79, 79. This runs on the rollers 80, 80 and 81, 81', the latter bein actuated when desired by gear 82, 82' sli ing on the shaft 83, 83' but turning with it when rotated by the hand-wheel 84:, 84'. The whole conveyer is supported on a traveling carriage 85, 85' having wheels 86, 86 running on track 87, 87' to advance the conveyer into position under rollers66, 66, or to return it to the position shown in accordance with the movement of rack 88, 88' attached to the carriage and actuated by pinion 89, 89', which in turn is actuated by beveled gear 90, 90' turned by the shaft 91, 91' and hand-wheel 92, 92. The distance between the rollers 66, 66' and 59, 59 is regulated by screw take-up bearings 93, 93' actuated simultaneously by a pair of beveled gears 94, 94' and cross-shafts 95 and 95 driven by beveled gears 96, 96' and handwheel 97, 97'.

The celluloid cake is placed in the hopper 57 falling down between the rollers 66 and 59' by which it is first broken up, the knife 67 being in the position shown, throws the fragments on the conveyer 70 by which the are continually returned over the top 0 roller 66 and again passed between the rollers. The rollers are then brought slightly nearer together and a blanket of celluloid gradually collects on and adheres to the roller 66. After the mass has all accumulated on this roller the return conve or is no longer needed and is swung bac to the left by the operation of the hand-wheel 78. The blanket is then cut from the roller 66' by throwing the knife 67 over against it by operation of the lever 69 and at the same time the conveyer 79' is advanced by operation of the handwheel 92 so that as the blanket is cut and falls from the roller 66' it is caught by the conveyer 79. When about onehalf the blanket has been laid on this advancing conveyer the movement of carriage 85 is reversed so that the blanket is folded upon itself as the carriage returns to the position shown. The return conveyer 70 may now be swung into the position shown, the knife 67 returned to the position shown, and the blanket of celluloid returned to the rolls by turning hand-wheel 78, causing the collection-apron to travel forward and deliver the folded blanket to the return conveyer 70 which carries it up until siezed hetween the conveyer and the roll 66' when it is forced between the two, and strikes the guide-plate 98 by which it is turned over and pushes in the pivoted side of the hopper and goes down again between the rolls When once more formed n :11 the roller amp ' collection-apron to the extreme left, and,

throwingthe knife'over against the roll 66 the thin sheet of celluloid is cut from the roller 66 and drops downwardly, and is collected' upon the apron 79 in a number of folds by moving the carriage 85' back and forth. When the blanket is all piled upon the apron 79' the thin sheet may be returned again to the roll and the operation repeate as many times as desired, to thoroughly work and mix the oods, removing only such portion of the so vent as is necessary to regulate its working and provide an em tremcly rich and, therefore, non-explosive atmosphere of solvent vapor in the chamber. The mass ma then be dropped through the spring trapoors 55' into the lower chamher where the same mechanical operations may be repeated, while removing as much of the solvent as is necessary to produce an impoverished atmosphere to render it nonexplosive. The impoverishment of the atmosphere may be controlled by regulating the action of the condenser 61, or if insufficient solvent remains to justify the recovery thereof, the bottom door 55 may be opened and the fans allowed to circulate air through the chamber thereby reducing the percentage of combustible vapor in the atmosphere below the lower explosive limit. For this purpose the casing 99 of the fans 57 may be conveniently made removable, or openings, 100, opposite the fans 64 may be provided. To regulate the temperature in either chamber heating coils 101, 101' are provided which are protected from fragments of celluloid dropping on them by a cover plate 102, 102'.

Referring to Figs. 4, 5 and 6 showin an apparatus adapted for the treatment 0 artificial leather and the like, 1 and 2 represent end walls of the apparatus, and 3, 4, 5 and 6 side walls, respectively, of a pair of drying-chambers. 7 and 8 represent the bottom and top, respectively, of the lower chamber, and 9 and 10, the bottom and top of the upper chamber. Partitions 11 in the lower, and 12 in the upper chamber, divide them into drying-chambers proper 13 and 14, and condenser chambers 15 and 16, each of the latter containin respectively, condensers 17 and 18 supp ied with a cooling fluid at a regulated rate or temperature. 21, 22, 23 and 24 represent bafiles in the drying chambers. In each of the drying-chambers 13 and 14 is located heating coils 19 and 20, respectively, and the upper chamber has an extension provided with a window 35 and a supply-pipe 26 leading from container 27 to supply jelly therefrom with which the web of goods 28 is to be treated.

Thisweb is suitably fed to the machine from the magazine roll- 29 passing over a grip ping roller 30 and retardin roller 31 into the extension through the s 01'. 32. In this extension the web receives the jelly 33 pass ing first over the supporting roller- 34, then under the doctor-knife 35- and over the suportin roller 36. Any excess of jelly falls om t e edges of the web into the trou h 37 and" is arranged to be withdrawn from t e machine in any suitable manner. In this extension a considerable quantity of solvent is evaporated from the jelly and the vapor passes into the top of the drying-chamber 14.

From the extension the web passes into the upper drying-chamber between suitable baflles 22, 2'3, 24 which direct the current of drying medium across its surface, and passing over supporting rollers 38 and 39' the Web is exposed to the heating drying medium so that it loses most of its solvent and maintains a high degree of saturation of the drying medium which is rendered possible by the elevated temperature produced by means of heating coils 20, and the only partially, and far flrom completed condensation produced by the cooling liquid flowing in the condensing pipes 18 at a moderately elevated temperature. From this chamber in which the medium is maintained in a state of high saturation, the web, freed from most of its solvent, passes through a tight slot 40 into the lower chamber 13 where the remaining portion of the solvent is to be evaporated, condensed and recovered. In this lower chamber the web passes over the feed roller 41 and gripping roller 42 and piles up in folds 43 on the belt, conveyer 44, being exposed for a long time in this chamber to the action of the drying medium which may be as hot as reviously, but which contains a much sma ler proportion of solvent vapor, which is more completely removed from the chamber, for instance, as by circulatin refri rated brine in the condensing 0011 17 or i y using cold water. This cold water becoming warmer may be used in the condenser 18 of the high saturation chamber. After becoming dry in the lower chamber the web passes between rollers 45 and around the tension roller 46, and is wound up on the magazine roll 47. It will beseen that by this means the solvent is recovered in two stages, in the first the goods being dried in an atmosphere so highly saturated with a combustible vapor as to be non-explosive and, in the second, in an atmosphere so largely depleted of combustible vapor as to render it non-explosi-ve.

It will be apparent that the use of mixed solvents produces mixed vapors, each constituent of which will. according to the natural laws, have its independent vapor pressure, andit is therefore possible to maintain the desired conditions above outlined, at a much lower temperature where mixed or complex solvents are used.

At a temperature of 20 C. the vapor tension of ethyl alcohol is 45 m. m., corresponding to the production of about a 6% vapor. If however, both methyl alcohol and ethyl alcohol are present, the methyl alcohol will have an independent vapor tension of about m. m., corresponding to 8% vapor. This makes a total of vapor tension of 110 m. m., corresponding to the production of about 14% vapor. While this mixture might not be entirely safe it willbe apparent that if benzol having a vapor tension at 20 C., of 76 m. m., be also a constituent of the mixture, it will tend to contribute 76 m. m., to the partial pressure, and make the total partial pressure of all vapors 186 m. m., corresponding to ap roximately 2l% of combustible vapor. hese partial pressures are only approximate, being individually influenced y the material mixed with the liquid or by other liquid being simultaneously evaporated or condensed, but they serve to illustrate this one valuable feature and aid in carrying out my inven-.

tion. It will also be apparent that during the second stage of the operation the impoverishment of the combustible vapor may be obtained in several difierent ways, either one of which may be used in conjunction with the initial treatment.

Ewamples.

First: The impoverishment may be brought about by admittingsuch an excem of air to the drying chamber as to increase the proportion of nitrogen and oxygen, and decrease the proportion of combustible vapor below that point at which the propagation of eplosion is possible.

Second: he va or of a non-combustible solvent such as car 11 tetrachlorid or a noncombustible fixed gas such. as nitrogen, may be made a constituent of the mixture or drying medium to such a degree that the explosive wave will no longer propagate therein.

Third: By adsorption or condensation of the combustible constituents of the drying medium they may be so far removed without afi'ecting the composition of the fixed gases that explosive propagation is no longer Fourth: The total ressure of all the vapors and gases may so far reduced that ropagation of the explosion wave is no onger possible.

Fifth: By substitution in place of constituents having a relatively low lower limit of explosibility, a constituent likewise exlosible but having a relatively high lower limit of explosibility.

The lower explosive limit of percentage of certain vapors is sufiiciently elevated that any one of these methods may be chosen which roves most convenient. However, the exp osive limits of percentage of other vapors are so low that a choice of the above methods, or a combination of them, may be preferable. But in general, any one of the above methods is ap licable in connection with the first stage 0 the recess.

While the treatment 0 excessively enriched vapors has been described as the first stage of the process, and treatment of excemively impoverished vapors has been described as the second stage, I do not desire to be limited to a process in which these two stages are thus successive in time. The order may be reversed, or they may be carried out in any other desired manner, although under certain circumstances it is advantageous to carry out, first, the stage mentioned as the first stage. Any suitable and well known apparatus may be used for carrying out my invention.

Although I have described my improvements in great'detail, and have specifically mentioned certain temperatures, pressures and other conditions which may be desirable in certain particular cases, nevertheless I do not desire to be limited to such details nor to such articular conditions except as clearly speclfied in the appended claims, since many changes and modifications may well be made without departing from the spirit and scoupe of my invention.

Havi in y described my improvements, what I c 'm as new and desire to secure by Letters Patent, is:

1. The method of handling combustible vapors evolving from material during the course of manufacture, which consists in treating the material in two stages, in the first stage maintaining the percentage of volatilized vapor in the medium surrounding the material so great that the medium is non-explomve, and in the second stage maintaining the percentage of volatilized vapor in the surrounding medium so small that the medium is non-explosive.

2. The procem of handling combustible vapors which consists in carrying out the process in two stages, in one stage maintaining the vapors in a condition of excessive enrichment to render them non-explosive, and in the other stage maintaining them in a condition of excessive impoverishment to render them non-explosive.

3. The process of recovering solvents evolved from material in drying operations which consists in condensing the solvents in two stages, in the first condensing only so much of the solvents as to maintain such a comparatively large percentage of solvent va or in the medium surrounding the materlal as to render the medium non-explosive, and in the second condensing and removing so mu'ch of the solvent vapor as to maintain such a comparatively small percentage of solvent vapor in the surrounding medium as to render the medium nonexplosive.

4. The process of handling combustible vapors evolving from material in drying operations which consists in treating drying in two stages, in one maintaining the drying medium in a non-explosive condition due to excess of combustible gas or vapor, and in the other stage maintaining the drying medium in a non-explosive condition due to excess of non-combustible gas or vapor.

5. The method of handling combustible gases evolving from material in drying operations and the like, which consist in handling them in two stages, in one stage adjusting the temperature, pressure, rate of evolution and removal of gases such that the ratio of combustible gas to oxygen is excessive so that the propagation of explosions is prevented, and in the second stage adjusting the temperature, pressure, rate of evolution and removal of gases such that the ratio of air to combustible gas is so great that explosion is prevented.

6. The method of handling combustible gases and the like evolving from material in drying operations and the like which consists in adjusting the temperature, pressure, rate of evolution and removal of combustible gases such that the percentage of combustible gases in the surrounding medium is beyond the limit at which, under the particular conditions of temperature and pressure, an explosion can propagate.

7. The process, of recovering solvents evolved in the manufacture of material which consist in carrying out the recovery in-two stages, in the first stage adjusting the temperature, rate of vapor evolution and removal of vapor such that the ratio of combustible vapor to oxygen in the surrounding medium is beyond the limit at which under the particular conditions of temperature and pressure an explosion can propagate.

8. In the manufacture of celluloid and similar material softened with solvents, the improved process which consists in first subjecting the material to a medium surcharged beyond the explosive limit with combustible vapor and heating the material, and further subjecting it to a medium too impoverished for the propagation of an explosive wave.

9. The method of handling a mixture of combustible gases mixed with non combustible gas in dr ing operations and the like, in which com ustible gas is evolved, which consists in suitably arranging the tem erature, pressure, rate of evolution, an removal of combustible gas in such a manner that the ratio of combustible gases to noncombustible gas is increased beyond the limit at which, under the particular conditions of temperature and pressure, an explosion can pnopagate.

10. The process of drying out and recovering solvents forming combustible vaors from material which consists in subecting the material to be dried first to a drying medium containing so large a percentage of solvent vapor as to render the medium non-explosive at the prevailing temperature and pressure, and then subjecting the material to a drying medium having such a small percentage of said combustible solvent vapor as to render the medium non-explosive at the then prevailing temperature and pressure.

11. The method of handling combustible gases mixed with non combustible gas in drying operations and the like, in which combustible gas is evolved, which consists in carrying out the treatment in two stages, in one stage suitably arranging the temperature, pressure, rate of evolution, and removal of combustible gas in such a manner that the ratio of combustible gases to noncombustible gas is increased beyond the limit at which, under the particular conditions of temperature and pressure, an explosion can propagate, and in the other stage suitably arranging the temperature pressure, rate of evolution and removal of combustible gas in such manner that the ratio of combustible gases to non-combustible gas is decreased below the limit at which, under the particular conditions of temperature and pressure present, an explosion can propa ate.

]2. he process of handling combustible vapors in drying operations and the like which consists in subjecting the material to be dried first to a drying medium containing so large a percentage of combustible vapor as to render the medium. non-explosive at the prevailing temperature and pressure, and then sub ecting the material to a drying medium having the ercentage of readily explosible vapor so ar reduced by the presence of other constituents that the explosive wave can no longer propagate.

13. The improved metho of treating volatile constituents in the manufacture of celluloid and other bodies softened with solvents, which consists in first manipulating the bodies in an atmosphere non-explosive by dilution of oxygen, and second, heating the bodies and completing the treatment in an atmosphere rendered non-explosive by dilution of the combustible constituent.

14. The improved method of treating combustible as, vapors or the like, in drying, and simi ar processes which consists in carrying out the treatment, first in an atmosname to this specification, in the presence of phere non-explosive by dilution of the oxytwo subscribin witnesses. gen, and second in an atmos here rendered 1AM M. GROSVENOR. non-explosive by dilution 0 the combusti- Witnesses: 5 ble constituent. GORHAM CRosLY,

In testimony whereof, I have signed my EDWIN Smmz.

Correction in Letters Patent No.1,143,623.

It is herebycertified that in Letters Patent No. 1, 1 43,623, granted June 22, 1915,

'- upon the application of William M. Grosvenor, of Ridgewood, New Jersey, for an improvement in Handling and Treating Combustible Gases and Vapors, an error appears in the printed specification requiring correction as follows: Page 1, line 33, for the article The read One; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed End sealed this 27th day of July, A. D.,1915.

R. F. WHITEHEAD,

Acting Oommiseioner of Patents.

[scan] 

